Steam Sensor - Bunn H5X Service & Repair Manual

SERVICE (cont.)
Steam Sensor (Thermistor)
Location:
The thermistor is located on the end of the overflow
tube above the overflow cup.
To test the thermistor, access will also be needed to
the electronic control board.
FIG. 17a LOCATION
FIG. 17b LOCATION
Test Procedure:
1. Disconnect the dispenser from the power source.
2. Disconnect the thermistor from J5 on control
board.
3. Check the resistance across thermistor with a
ohmmeter. The resistance range is approximately
9K @ room temperature to approximately 2K @
200°F.
4. Disconnect the dispenser from the power source.
If resistance was present as described, the thermistor
is working.
If resistance was not present as described, replace the
control board.
Removal and Replacement:
1. Disconnect the dispenser from the power source.
2. Disconnect the thermistor from J5 on control
3. Loosen the set screw and the two screws securing
4. Install new thermistor on tube and slide down until
5. Snug the set screw so the block assembly does not
6. Connect the thermistor to J5 on control board.
NOTE: DO NOT TEST OPERATION WITH PANELS
H 5X ®
P1993
Set screw
H 10X
P1993
17
board.
the two half blocks together. Remove thermistor
assembly from overflow tube.
it contacts the flared end. NOTE: It's critical that
the thermistor be centered directly under the tube
opening.
move aroung easily.
REMOVED, AS AIR MOVEMENT CAN HINDER
PROPER READINGS ON THERMISTOR.
Mounting screws
FIG. 17c STEAM SENSOR EXPLODED
FIG. 17d THERMISTOR POSITION
DO NOT BEND
THERMISTOR
UP/DOWN
Thermistor centered
under tube opening